mysql4.0做主从时主库的备份脚本
mysql4.0是老版本了，但是有些早期使用的企业依然在用，在创建主从时特别是线上服务器创建主从时，保证数据的一致性是个大问题：比如创建完从库同步时出现重复数据重复执行（虽然数据条数一致，但数据有可能会不一致）等。
在mysql5.0以上版本中，此时备份主库只用在mysqldump时加上-F、master-data=2，single-transaction参数，从库同步时导入备份，在取备份文件开头的bin-log和pos位置进行同步即可，不会出现数据重复执行等问题，他能确保同步时的一致性。比较悲剧的是，本人所用的
数据库还没有升级，是4.0的版本，经过测试，写了一个专一用于4.0主从同步时主库备份的脚本，原理就是模拟5.0以上的备份过程来做的。也可以用于5.0以上的版本，但是5.0以上的版本没有必要这么做。大家可以参考。
#!/usr/bin/env python
# -*- coding: utf-8 -*-
www.2cto.com
import os,sys,time,MySQLdb
import subprocess,threading
class
mysql_dump():
def __init__(self):
self.dumpname = "/root/alldata%s.bz2" % time.strftime("%Y%m%d%H%M")
self.STAT_IP = "192.168.0.39"
self.logfile = "/root/mysql_dump.log"
self.user = "root"
self.passwd = "1q2w3e4r"
def log_w(self,text):
now = time.strftime("%Y-%m-%d %H:%M:%S")
tt = str(now) + "\t" + text + "\n"
f = open(self.logfile,'a+')
f.write(tt)
f.close()
def dump(self):
cmd = "/usr/local/mysql/bin/mysqldump -A -Q -e --add-drop-table --add-locks --extended-insert --quick --no-autocommit --single-transaction -u%s -p%s | bzip2 -2 > %s" % (self.user,self.passwd,self.dumpname)
print time.strftime("%Y-%m-%d %H:%M:%S")
text = "Start mysqldump,Please wait ..."
print text www.2cto.com
self.log_w(text)
a = subprocess.Popen(cmd,shell=True)
while 1:
b = subprocess.Popen.poll(a)
if b == 0:
text = "Mysqldump complete"
print text
self.log_w(text)
break
elif b is None:
print 'Mysqldump running'
time.sleep(30)
else:
print a.pid,'term'
break
self.rsync()
def rsync(self):
cmd = "rsync -az %s %s::asktao_db/db_back/" % (self.dumpname,self.STAT_IP)
text = "Start rsync to server(%s) ,Please wait ..." % self.STAT_IP
print text
self.log_w(text)
a = subprocess.Popen(cmd,shell=True)
while 1:
b = subprocess.Popen.poll(a)
if b == 0:
text = "Rsync complete"
print text www.2cto.com
self.log_w(text)
break
elif b is None:
print 'Rsync running'
time.sleep(30)
else:
print a.pid,'term'
break
def lock(self):
try:
conn = MySQLdb.connect(host = '127.0.0.1',user = 'root',passwd = '1q2w3e4r', charset='utf8', connect_timeout=5)
cursor = conn.cursor()
text = "flush tables with read lock"
print text www.2cto.com
self.log_w(text)
cursor.execute("flush tables with read lock")
text = "flush logs"
print text
self.log_w(text)
cursor.execute("flush logs")
d = threading.Thread(target=self.dump, args=())
d.start()
while 1:
if os.path.isfile(self.dumpname) and os.path.getsize(self.dumpname) > 0:
text = "UNLOCK TABLES"
print text
self.log_w(text)
cursor.execute("UNLOCK TABLES")